This invention relates generally to an improved opening roller for an opening device of an open-end spinning arrangement having a roller body that is connected to a shaft. More specifically, a ring mounting or fitting ring arranged on the roller body is provided with teeth on its circumference.
It is currently the practice to use opening rollers in open-end spinning arrangement having teeth in the form of a saw-tooth wire wound directly onto the roller body circumferential surface, or onto a ring mounting. The shape of the teeth has a considerable effect on the efficiency of the opening process and is designed in accordance with the fiber material to be processed. In order to protect the relatively fine teeth against mechanical damaging when the opening rollers are being handled during transportation or storage, collars are usually provided which are unitary with the part carrying the teeth, i.e., the ring mounting or the roller body.
DE-OS 19 39 683 discloses an opening roller of the type described above, wherein a ring mounting is provided which has teeth formed in one piece by the formation of at least one surrounding groove and several recesses extending in an axial direction. The ring mounting protrudes over the roller body on both sides in an axial direction. Due to the presence of axially extending recesses, it is not possible with this type of construction to mount collars at the ring mounting which can protect the teeth against mechanical damaging during transportation or storage. In this type of construction, the teeth must therefore be designed to be very strong, thereby presenting considerable limitations with respect to tooth shapes that can be used. Also, an obtuse vertical angle is provided between the tooth face and the back of the tooth. Because of these disadvantages, an opening roller of this type has not been in practice.
As discussed, the shape of the teeth has a considerable effect on the efficiency and effectiveness of the opening process. Further, the shape and dimensions of the teeth are very important in both achieving proper opening of slivers into individual fibers and preventing damage to the fibers, and this factor must also be balanced with teeth which are resistant to wear. During manufacturing of the rings for opening rollers, it is important to take into account all of the above factors, including shapes, dimensions and materials, as well as additional factors.
It is known to use saw-tooth wire for either card clothing, which forms slivers, or for opening rollers which open up slivers into individual fibers. The saw-tooth wire is wound around a support cylinder of some type. The saw-tooth wire is in the form of a strip having teeth cut out. On lateral faces of the wire, a projecting edge is provided such that when the saw-tooth wire is wound into a coil, abutting lateral faces will create circumferential grooves between rows of teeth. The methods involved in forming cylinders having teeth formed by saw-tooth wire are widely divergent from the methods of forming a solid ring having teeth. Further, certain additional factors must be considered with saw-tooth wire arrangements, such as a support structure disposed underneath the saw-tooth wire. On the contrary, solid rings support themselves, and thus do no require a supporting cylindrical inner element.
For increasing resistance to wear, hardenable materials such as steel alloys are desirable. However, the steel alloy has a greater mass than known aluminum arrangements. Thus, dimensions should be kept as low as possible such that the ring formed does not have an undesired high mass. Further, it is desirable to have an opening ring of a single material to facilitate any subsequent wear resistant coating applications. In certain prior arrangements, metal saw-tooth wire had been applied to an aluminum support. The different materials sometimes complicated subsequent coating processes.
As discussed above, the dimensions of an opening roller ring and the teeth arrangement thereon are highly critical for the specific purposes of opening up slivers into individual fibers. To form these highly specific dimensions required for a hardened steel alloy opening roller ring element and the teeth arrangement thereon, specific advantageous processes are needed.
It is thus an object of the present invention to provide a process of manufacturing an opening roller assembly, including the formation of a solid opening roller ring mounting or fitting ring having highly specific dimensions and teeth arrangement critical for the specific purpose of opening up slivers into individual fibers.
It is a further object of the invention to provide a method of manufacturing such a ring made of a hardenable steel alloy material, while keeping total mass as low as possible without sacrificing durability and resistance to wear.
It is a further object of the present invention to provide precision in the formation of very small, slender and fine teeth on an opening roller ring, as deformities in such a precise fine arrangement may hinder the opening process.
These objects and other objects are achieved by providing a method of manufacturing an opening roller assembly for an opening roller of an open-end spinning machine which includes forming at least one circumferential groove in an outer surface of a hardened steel alloy cylindrical sleeve. The circumferential groove creates circumferential webs having lateral flanks delimited by the circumferential grooves. A wall section is created in the cylindrical sleeve from which the circumferential ribs or webs extend outwardly. The radial thickness of the sleeve wall section should be no greater than 2.2 mm. The base thickness of the circumferential ribs should have a thickness of no greater than 0.7 mm. The sleeve wall radial thickness should be about 0.60-0.72 times the height of the circumferential ribs. The circumferential grooves should have a base width of about 2.5 to 3.5 times the base thickness of the circumferential ribs. Next, at least two axially extending axial or longitudinal grooves are formed across the cylindrical sleeve circumferential ribs, thereby forming combing teeth having fine tooth points and a slender shape for opening slivers into individual fibers on the outer surface of the cylindrical sleeve. The axial grooves form front and back faces on the teeth which have lateral flanks formed by the circumferential groove.
The hardened steel alloy material used for the ring provides superior wear resistance. The maximum thickness of the ring wall of 2.2 mm provides a metal ring that does not have too high of a mass. Further, as the steel alloy is hardened, the teeth are uniformly hard over their entire height and thickness, as well as in the area where the teeth extend from the sleeve wall. This results in much improved wear characteristics. By using already hardened steel alloy for the ring, precisely formed teeth can be formed without requiring a subsequent hardening which may deform teeth.
According to advantageous features of certain preferred embodiments of the invention, the circumferential grooves and the axial grooves are ground into the hardened steel alloy sleeve. Although it is preferable to only use grinding, it is also possible to first cut the circumferential groove by way of turning or a lathe, and then subsequently gring the groove. As the circumferential ribs formed by the circumferential grooves are so thin (no greater than 0.7 mm in the base region), grinding is the best method as it forms precise rib dimensions required in the area of opening roller art.
Further, as the axial grooves are formed in the very fine and thin circumferential ribs, grinding is the most appropriate process to be used. Grinding provides the precise and delicate dimensions of the teeth of the opening roller ring. The grinding of the ring element provides very good concentricity and does not require an expensive balancing process of the ring element after the teeth have been formed. The ring element will be subjected to extremely high speeds of rotation such as velocities of about 3,000 to 12,000 min.sup.-1. To ensure accuracy and to assure smooth operation with reduced noise, the rings should be properly balanced when rotated. The present invention process produces a ring element of such precision that the produced ring element is already balanced without requiring a subsequent balancing operation.
The grinding of the grooves provides high surface qualities along with the precise dimensions required in opening roller construction.
In certain preferred embodiments, the ring mounting has a hardness of about HRc60+3.
According to other advantageous features of certain preferred embodiments of the invention, the teeth of the ring mounting are electrolytically or chemically deburred (etched) after the grooves are formed. This process is not merely a removal of burrs from the surface of the teeth, but precisely rounds off by cutting or etching the sharp edges of the teeth formed during the grinding steps. These rounded off edges are highly desirable for opening roller teeth to provide the most efficient and effective opening up of a sliver into individual fibers without damaging the fiber material. In certain preferred embodiments, the edges of the teeth are rounded off such that they have a radius of curvature in the range of 0.02 mm to 0.06 mm. In certain preferred embodiments, the radius of curvature of the rounded edges should be about 0.04 mm.
According to other advantageous features of certain preferred embodiments of the invention, the ring mounting, at least in the area of the teeth, is provided with a surface coating after the shaping of the teeth. Examples of suitable chemical coating include a diffusion treatment with nitrogen and carbon, or a metallic coating. Especially preferred is a coating which includes a chemically applied nickel layer with embedded diamonds. The wear resistance of the opening rollers can be improved, especially in the area of the teeth when a surface coating is applied to the already relatively hard steel alloy base.
Other objects of the present invention include providing an opening roller which is not subject to limitations with respect to the development and design of the teeth which may be broken off subsequent to forming. This object and other objects are achieved by bordering the ring mounting on each side with collars extending in the radial direction to approximately the tops of the teeth. These collars are mounted on that portion of the roller body that axially projects beyond the ring mounting on both sides. By means of these collars, teeth that are integral with the ring mounting are protected so that very finely shaped teeth can be used without danger of being damaged.
According to other advantageous features of certain preferred embodiments of the invention, at least one of the collars is detachably mounted on the roller body. This makes it possible to replace the ring mounting, thereby reconstructing the opening roller. By means of the detachable collar, it is also possible to clamp the ring mounting so tightly to the roller body that it is held securely in place.
According to other advantageous features of certain preferred embodiments of the invention, at least two surrounding grooves that are sloped in opposite directions and cross one another are formed into the ring mounting. This results in very finely shaped teeth having a very good combing effect.
According to advantageous features of certain preferred embodiments of the invention, the ring mounting is equipped with surrounding grooves that are sloped in opposite directions and extend from the axial center of the ring mounting. This makes it possible to position the fiber material (sliver) to be opened up in a desirable distribution over the working surface of the opening roller; i.e., to concentrate the fiber in the direction of the center of the working surface.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.